1. Field
The present invention relates generally to sound barriers and more specifically to a system for absorbing sound waves emanating in particular from highways, railroads, and similar transportation structures.
2. Prior Art
Since the advent of complex motorized transportation systems, such as railroads, automobiles and airplanes, there has been a need to prevent noise caused by such systems from effecting surrounding neighborhoods and businesses. Consequently, a number of devices and systems have been created which have been somewhat effective in eliminating said noise.
Common barriers such as fences constructed of wood or a similar lightweight material probably served as the first noise barriers. While effective in preventing sight access, such barriers are quite ineffective in preventing the transmission of sound waves.
Concrete or masonry barriers and barriers constructed of a similar heavy material are perhaps more commonly used in attempting to prevent noise transmission. Barriers constructed of concrete are far superior to wood structures in accomplishing this goal, and yet it has been determined that concrete barriers and the like tend more to deflect sound waves rather than to dampen or absorb the same. Hence, while these types of barriers seem to be suitable for the accomplishment of some tasks along a highway or railroad track, they leave much to be desired in the area of preventing sound wave transmission.
Lately, much experimentation has been done with barriers having extruded hollow members, particularly those which are modularly connected together, some of which are constructed of thermoplastic materials which absorb rather than deflect noise waves. Such structures may be effective in dampening much of the noise generated by highway traffic, locomotives, airplanes, and the like, although these barriers are not as effective as desirable. Furthermore, many of these barriers ar constructed of materials which break down quickly or lose their resiliency when subjected to adverse conditions such as extreme weather and high-velocity impacts with foreign objects.
Therefore, there exists a legitimate need in the art for a durable sound barrier system which is more effective in dampening sound waves propagated by complex transportation systems. Such a system would advantageously be resilient and capable of surviving modest impacts, and also be capable of some structural support functions.